Electric furnace.



PATPNTBD OCT. 1, 1907.

J.- T. MARSHALL. ELEOTR1G.PURNAGB. urmonxon rum uu. 26, 1907.

2 SH PETS-SHEET l.

lnv'enbor I dohn-TMav' hall,

WHinesses: r

-Abby.

which ihc JOHN. T. his

5.15., Cd MEP'UCHIEN, NE? JERSEY, ASSTGNOPt- TO A CORPORATION OF NEW YORK.

GENERAL ELECTRIC ELECTRIC FURNACE.

i No. 867,519.

Specificationof Letters Patent.

Patented Oct. 1, 1907.

Application and January 26,1907. s m no. 354,222.

To all whom it may concern:

' "Be it known'that I, JOHN T. MARsnALL, a citizen ofv the United States, residing at the borough of Metuchen, county of Middlesex, State of New Jersey, have invented certain new and useful Improvements in Electric'Furnaces, of which the following is a specification. This invention has for. its object the rapid and uni form production of the socalled metallized filaments for incandescent electric lamps. Such filaments are manufactured by subjecting the usual carbon filament to excessively high temperatures in an electric furnace for e consrierable period of time. i i The 1 1' ',0Cilt invention consistsof a furnace in which the carbons are thus treated. It is found that the st must be applied for about one hour or less, after filaments are allowed to cool off. The furrefore arranged to permit a plurality of sets of filzunents to be treated in succession, the heating deug moved from one set to the negctat the end (H1 hour. The heating app iances comprise a carbon tube in which the filaments areinclosed, and a body of graphite or the like in which the tube is embedded to retain and equalize the heat. The ends of the tube are held in metallic sockets which project through the walls ofthe furnace and are adapted to receive the terminals of the secondary of a'trarisformer.

A carriageis arranged to support the transformer in convenient relation to the plurality of tubes, so that the transformer can be moved alongh'om one tube to the next as desired.

i In the accompanying drawings, Figure 1 is a front elevation ofone. end of a furnace embodying my invention, Fig. 2 shows the boat in which the filaments are packed; Fig. 3 is a cross-section of the furnace, partly in elevation; Fig. 4 is a longitudinal section of one of the metal sockets, and Fig. 5 is across section of the same on the line 5 5, Fig. 4.

The'body 1 of the furnace is a box-like structure of brick or cement, having an open top. ,In its side walls are a plurality of openings, those in onewall being directly opposite those in the other wall. In eac ing is mounted a metal socket 2,-which is capa ready removal, and has double or hollow fills, in order to provide for the circulation of water or )Iillfil' US- through a pipe 3 at one side of the socket, and led off cooling medium. The water may be intro by another pipe from the other side, and in order to insure a complete circulation Erom end to end ofthe socket, it may be divided by webs 4 into two chambers The webs do not extend quite to the inner end of the socket, so that the two chambers communicate at this point. The water may if desired be conducted from one socket to another, by the pipe 6, flowing in series through the entire set on one side of the furna-ce.

I In each end of the socket is a tapering recess, the inner one being preferably the larger. This inner recess 7 is for the purpose of receiying the tapering end of a carbon tube 8. If desired, it carbon bushing 9 may be interposed between the tube and the socket.

The furnace is filled with a loose powdered material 10 capable of standing a high temperature, such as artificial graphite. The tubes are embedded in this material, as shown.

Along the top of the furnace is laida track composed of rails 11, and on this track is mounted a carriage having a floor 12 and truck wheels 13. The latter are flanged to keep them on the rails, and one of the axles 14 is provided with one or more crank handles 15 by means of which it can be rotated to cause the carriage to travel along the track. On the carriage is supported one or more transformers 16, of suitable capacity for the work intended. The loads 17 connected with the primary coils of these transformers are connected with trolley shoes 18 which are spring pressed against the undcr side of the stationary parallel comluctors l erected above and parallel with the furnace, and connected with a suitable source of alternating current. The secondary leads 20 of the transformers are connected with two plates or bars 21, preferably of copper, which are secured to tubular terminals 22 having tapered ends adapted to enter the outer recesses 23 in the sockets 2, one terminal being at the front of the furnace. and the other at the rear.

Each terminal is supported by an upright lever 24 suitably pivoted to the frame of the carriage; as by means of trunnions 25 journalcd in eyes at the ends of straps 26 bolted to a cross bar 75 projecting laterally from the carriage. The lovers are composed partly of wood 28, or some other non-corulucting material. and at their upper ends are swivclcd collars 21) through which passes a shaft or rod 30. Onc or both of these collars is screw-threaded to form a. nut meshing with threads 31 on the shaft. Handles 32 cnablo the operator to rotate the shaft and thus oscillate the lovers, whereby the terminals 22 will be forced into the sockets or withdrawn therefrom as the case may be.

Attached to cach terminal and in line with its axis and that of the carbon tube 8 is a tubular handlo 33 by vi which the operator can apply the terminal t tl' socket. an opcratm' being stationed on oath sidc of the l'urnacc to manipulate the two terminals.

The operation of the apparatus is as follows: \Vhcn the carriage has been brought oycr the desired pair of sock ts. the terminals are applied to the outer rcccsscs thorcidand tho hand wheel is turned to force them into close contact. The currcut flowing through the carbon tube 'hcats it to an intensely high temperaturc. A graphite boat or trough 34 is fill it with th. e filaments to be treated and is pushed l g the inoved' ztlong to "the'nextzp'eij of sockets;

tubhliir handle; end terininglj'into the jearbon tube wghero'it isvallowedto re'mein' un il' the filaments hayef A changeof tubes onlyon'ce in a gay l- When the tubes ere ft'obe replaced fresh; ones; "the peckingis "removed from over the first one,- and'one-'of the sockets is withdrawn enough to ellowith'e tubeto be out mdj'a new'one put in and-the socket shoyed in against it, The second'tiib'e is tlienluncoverjed, the packing lar teeminuls zidzipted to inz ke eontact with seidsoekets;

tlmel. .The pressure exel'tted"-by the n" miilies' all-the connections tight, the ite min s sockets and. tube. ion hing one tight: continuous. tube through "which the'mat'el igil to be metitll ized be-pissed very r eedfly-flf T desired, "g e's they be' int 'oduced' into the 'tube'by-tneens of thetconneetion -bfi.

' What .1- cleini as'nw and desire-to secure by Letters Patent of the United Stat'es, is:- Y 1'. An 'lectrie fut-nope comprising a pluralityfof'tubegla-so'u're {of alternating current, and movable terminals 2. An electric furnaee comprising a plurality of ca 'bo'ntubes, a, source oiiialter'nlting current, movable tel'inlnals therefor, and ineans' fol: forcing said terminalsjnto good eglectrjbabconnection with anyone 6: 5am tubes. 7 v

3. An electric furnace comprlsinge plurality-of ea rbon tubes, in'etal sockets for holding the ends-of said tubes, and

movableterminals-steamed to be forced into conte'ct with. said-soekets,.' I at. An electric furnace compi-ising a pl n-ality of carbon tubes, and tubulai' tei-ininals aZIapted -to be connected with the ends of tiny one ofsa id tube s. 7' 5.: An elec ti-ic furnace comprising e. pluralityof eel bon-j tubes; tubular-sockets for thesends of said tubes, anittnbn;

6. "An eleetl-ic furnace c'omprisl'nge plurality of ciii'bon;

tubes, hollow n e tal sockets forrece iving the ends of said tubes, and means; ton-feeding a cooling fluid oth voughsaldi sockets,

v7Q Anlele'cti'ic ftiitnece-eonlpi-ising a ilurality o'fca rbon tubes. :1 carriage-adapted to ti'oveltrans vei-se to sait l tubes,-

and movable terminals supiioiftetl on saidcal-ridge.

"S. An electric furnace eompi ising a pluvtility ot-eii 'bon tubes. :1 curriage-eqaptezl totl'zivel transverse to sui tubes;-

crew

'- eel-hon tubes a'i rangetl transversethereto; removabletubue lei-sockets in the \vallsof said st ru'etjn je 'foi'fholding' the;

-, ends of; said Itubes, a eai-ringe movable along the on of; said;

I structure, tubular terminals chlft'ledby sii ld czii 'lag tubes. aqepted "to-be conneete isu'ccessively to the ends of said"- "tubes;-

'with the ends of sold 9. 'An electric fui'na e 'c0nipi'1sfng x plurality of .em bon tubes, :1 chri-iageadeptedto t avel'trnnsverge to said tubes, -levers pivoted oms'aideapripgfi "and terminalsncurrieq by said leversf v '10. An electrle'tu -nace: 'comprlslng a 'plurelity of carbon ,tubes, e eon-loge edepted to traveltiansverseio' said tubes,

level-s pivoted on' said cai'rlage, ite 'mlnals'eerrled bysii leveis-and'ineans I011 moi ing said lev'ers toftorce sald tierminals into'goodelectrical. c'onneetlon with -the'nds any one of said 'tubes. 7 l

11 An electrieltui'nuce comprising a olui allty' 'o'F'cfa -bon tubes, 11 'cari iaee adapted to travel transverse mould-tubes,-

le'jvevs pivoted; on said chi-tinge;tei inlniflsfeaified hi and. levers, means fob-moving said levepsjt'offoicesalq tei nl'ngla: intogood electrieail connection with the-'en dsof aliy oneot. fsalid tubes, seiduneansgconsjstlng of a shatb serewrth 'eiidq conn'ection with one of l'eyers and having a both thereof.

12-. Anselect 'iefui-naee jeeniprls in'gie'box lihe;Striic: "i-e,

carbon tubeseM-anged t 'ansversethiereto, i eerr lage inovi: able-along the top of said furnace, and teiunlnal'sfcin 'id said carriage and ad'iipteditdmake eohtactwlth'theiehdsjotany one of sald'tubes.

' v 13; An electric fl'irnace eoinpi-isin'g e.- boxl-tke structure,-

means for forcing them lnto c'ontne't-wlth said l sbeketi.

-1 4. An eleeti-ic' furnace comprising'a-jboltzlike st zuotufe; Cal-hontubes trunsyerse thereto} a" cni i'ln'ge movable Mon; the top ofsaid'stiueturma tl' ilnsfornl rlage, and movable seconderyte'rininiils ;th er f91j'a di1pted="to 15. An electric furnace eonip -lslngj'e boX Iike structure,

and tubular teir'mlnails' auppm-tedon carriage-infline 95 sockets in the walls of. the;box=fo r holding the endspf s'nld tubes. a carriage novuhleamng the top of said box; levers pivoted on snid c a 'i'iage-und earr-ying terminals atlnptedato engage'witll the sockets. and :i'trnnstoi-inei' 'oni'sn-id cal ri aige having its second ui' coil s connectedlwithfis aiqtel'ln inelsq I16; An electrlcgfurnae'e comp -is'ingn bo2;-like structure,

. a filling of. loose reftactory niutei ial; .curbon tubes 'eitend l in'g uci'oss said box belov v the sin-face or "the fillinglinetiil :sockets in, the 115' of th'elboi foi'holding" the entis' ot'sa'ia tubes, :1 carriage-movable 'along fihe top 'ot; s nid whogleve s :pivoted ,on said caiiriege. and. chi'ryin tei n inqls ada-fit'eti 10 on said Eon-in":

engage with the sockets-ja transformer 'ihg vlngq.its-secondaryl colleoon'necteo .ufltli saitl tei m'i nnls'}; fandahserew' shaft uniting siiid lev'e i s foif simultgmeouslj 

